OBJECTIVE: To determine the extent to which depressive symptoms are associated with heavy cannabis use in an Aboriginal population in Arnhem Land, Northern Territory. DESIGN, PARTICIPANTS AND SETTING: Cross-sectional study involving interviews with 106 Indigenous participants (57 males, 49 females) aged 13-42 years in three remote Aboriginal communities in Arnhem Land, NT, Australia. MAIN OUTCOME MEASURES: Measures of depressive symptoms (a raw score of > or = 6 out of a possible 18 on a modified version of the Patient Health Questionnaire-9) and self-reported heavy cannabis use (six or more cones daily). RESULTS: After adjusting for other substance use (tobacco, alcohol and lifetime petrol sniffing), age and sex, heavy cannabis users were four times more likely than the remainder of the sample to report moderate to severe depressive symptoms (odds ratio, 4.1; 95% CI, 1.3-13.4). CONCLUSIONS: Given its high prevalence in Indigenous populations, the development of clinical and prevention strategies for cannabis misuse are warranted.